So all your water comes from the ocean? Sand and rocks also? How long have they been in your tank?
They could also have die off that add to an amonia spike, water, rocks, and sand.
As for your stingray:
YELLOW STINGRAY
Order: Rajiformes
Family: Urolophidae
Genus: Urobatis
Species: jamaicensis
Taxonomy
The yellow stingray is a member of the Urolophidae (round rays) family. This ray was first described by Cuvier (1816) as Raja jamaicensis. The current nomenclature for the yellow stingray is Urobatus jamaicensis (Cuvier 1816), however most of the literature concerning this ray can be found under the name Urolophus jamaicensis (Cuvier 1816). Junior synonyms include Trygonobatus torpedinus Desmarest 1823 and Urobatis sloani vermiculatus Garman 1913. The currently valid name Urobatis jamaicensis gets its genus name from the Greek words "oura" = tail and "batis" = a ray
Common Names
While Urobatis jamaicensis is commonly call the "yellow stingray", it has also been referred to as the "round stingray," "yellow spotted stingray," and the "maid stingray." There are many common names for this ray, including Jamaicaanse doornrog (Dutch), pikkukeihäsrausku (Finnish), trygon jamajski (Polish), tembladera (Spanish), raya (Spanish), and raya pintada (Spanish).
Distinctive Features
Like other rays of the Urolophidae family, the yellow stingray is characterized by a round body. U. jamaicensis has a well developed caudal fin that extends around the tip of its tail. The tail spine is located just anterior to the caudal fin. The distance from the tip of the tail to cloaca is shorter than the distance between the cloaca and snout. Additionally the posterior edge of the pelvic fins are rounded.The yellow stingray lacks a dorsal fin.
Size, Age, and Growth
To date no study has examined age and growth of U. jamaicensis. Observational data indicate that yellow stingray grows to 26 inches (66 cm) in length with a maximum disc width of approximately 14 inches (35 cm). Examination of the condition of the claspers suggest that males are sexually mature at a disc width of 15-16 cm.
Food Habits
While there is no literature describing U. jamaicensis feeding habits, its method of prey capture may be similar to the round stingray, U. halleri. The round stingray has been observed to scoop out large holes in the muddy or sandy bottom by "waving" its pectoral fins. This action serves to expose any buried worms, crabs or small fish. It has also been suggested that the yellow stingray may attract prey by raising its snout to create a shady area for small fish to hide
Predators
Any large carnivorous fish, especially sharks such as the tiger shark, is a potential predator of the yellow stingray.
Parasites
Cestodes such as Acanthobothrium cartagenensis, Phyllobothrium kingae, Rhinebothrium magniphallum, and Discobothrium caribbensis are among the endoparasites associated with the yellow stingray.
Danger to Humans
Like most rays, the yellow stingray presents little danger to humans. Stingrays only use their venomous tail spine as a form of defense. Stepping on a stingray is the most common way people are injured by these fish. While being stuck by a stingray spine can be painful, it is rarely life threatening.
Conservation
While not a commercially targeted species, the yellow stingray may be a source of by-catch. Additionally, populations of the yellow stingray can be influenced by a loss of habitat and a reduction in prey sources. U. jamaicensis is not currently a listed species with the World Conservation Union (IUCN).
I like it!!
